Your in the line of the l2 or l3 if you want that size heads for conventional, or an N5, R5, or N6, R6 for rotary. If you go with the N series, make sure it is atleast a 1982(series 3) or newer. The earlier N's weren't built as heavy or as well and had way too many updates. All of these machines should be able to be bought with heads for under $25,000, the R being the most expensive. The rotaries are by far better if you plan on corn and soybeans. I now own an 82 N6 that is Hyperized and is one fantastic machine, it well out performs my uncles 2388 and the neighbors 9750STS with the same size heads. And I put a fraction of the dollars in it as they put in theirs! If you watch around too, I have seen several N's and R's with Cummins conversions.